Recently, in an active-matrix liquid crystal display device including a switching element in each pixel, a structure using a lateral electric field such as an in-plane switching (IPS) mode has been put into practical use. Such an array substrate for a liquid crystal display device of the lateral electric field mode includes a pixel electrode and a counter-electrode, and the alignment of liquid crystal molecules is controlled by a lateral electric field which is substantially parallel to the main surface of the array substrate.
With respect to this lateral electric field mode, there has been proposed a technique of controlling the alignment of liquid crystal molecules by producing an oblique electric field between a pixel electrode formed on the array substrate and a counter-electrode formed on the counter-substrate. Above all, a technique of producing an oblique electric field by combining a cross-shaped pixel electrode or an I-shaped pixel electrode and a common electrode disposed above source lines is proposed.